Equalizing unlock and impulse action escapement.



B. A. GOCHRAN.

BQUALIZING UNLOCK AND IMPULSE ACTION ESGAPEMENT.

APPLIOATIOH FILED mar. 25, 1912.

1,105,062. Patented July 28, 1914.

4 SHEETS-SHEET 1.

WITNESSES: IN VEiITOR Amomw EY THE NORRIS PETER S ca PHOTD-LITHO. WASHINGTON. D. c.

E. A. GOGHRAN.

EQUALIZING UNLOCK AND IMPULSE ACTION ESGAPEMENT.

APPLICATION FILED JUNE 25, 1912.

Patented July 28, 1914,

4 SHEETSSHEET 2.

I INVTOR flward/fkzram WITNESSES VC 0. N m a m H M w m H m o H P 0 C s m T E P w R R o N E m B. A. COGHRAN.

EQUALIZING UNLOCK AND IMPULSE ACTION ESGAPEMENT.

APPLICATION FILED JUNE 25, 1912.

1,105,062. Patented July 28, 1914.

4 SHEBTS'-SHEET 3.

WITNESSES:

Amour: my

INVENTOR B. A. GOGHRAN. EQUALIZING UNLOCK AND IMPULSE ACTION ESOAPEMENT.

APPLICATION FILED JUNE 25, 1912.

Patented July 28, 1914,

4 SHEETS-SHEET 4.

THE NORRIS PETERS (30.. PHOTO-LITHQ. WASH NGION, D. c

UNITED STATES PATENT OFFICE.

EDWARD A. COCHRAN, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR OF ONE-FOURTH TO JOE STEINER, OF SAN FRANCISCO, CALIFORNIA.

-EQUALIZING UNLOCK AND IMPULSE ACTION ESCAPEMEN'I.

Specification of Letters Patent.

Patented July 28, 1914;.

Application filed June 25, 1912. Serial No. 705,707.

To all whom it may concern Be it known that I, EDWARD A. Coornn-xn, a citizen of the United States, residing in the city and county of San Francisco and State of California, have invented new and useful Improvements in Equalizing Unlock and Impulse Action Escapements, of which the following is a specification.

My invention relates to escapcments for time-pieces for that class known as double roller escapements.

It consists in a novel construction of the roller, jewel, dart and fork and in details of construction which will be more fully explained by reference to the accompanying drawings, in which Figure 1 is a plan View of the improved visible dart escapcment. Fig. 2 is a side View of the roller table. Fig. 3 is an enlarged detail of single roller and guard tines. Fig. t shows a double roller escapement. Fig. 5 is a side view of same. Figs. 6 and 7 show a variable dart'escapement. Fig. 8 is a front view of the roller table of Fig. 1. Figs. 9 to 13 inclusive illustrate the action of the roller jewel during a cycle of the escapement.

My present invention comprehends the employment of a roller table, impulse jewel, dart and pallet lever,all of which are peculiarly designed with the object in View of improving the mechanical efliciency of the parts, both as to their mode of operation and to the increased durability and strength of the delicate parts involved in watch escapements.

In my escapement I employ a roller table, 9, having the usual staff 3; the roller table being provided with a jewel 4 set in a peripheral recess or seat 5, which recess is preferably V-shaped with its acute angle intcrsecting a radial line of the roller table.

One of the important features of this in vention is the peculiar shape of the jewel 4.

and its mounting. The jewel 4c is here shown as comprising a wedge shaped block or sector; the apex being set into the seat 5 so that the base of the wedge or jewel is arranged more remote from the center of the roller table than the apex of the jewel. The base of the jewel is supported by the adjacent sides of the jewel seat 5 in the roller table 2 and receives the blow between two points of support.

In Figs. 1 and 2 the roller table is shown as provided with substantially diametrically opposite, peripheral, arcuate flanges 6, the perimeter of one of which is designed to coincide with the base of the triangularshaped jewel 4, which is arranged in the roller table with its apex parallel to the axis of the roller table and the other flange 6 acts as a counterpoise, the table being cut away for lightness. I

.One of the immediate advantages of a wedge-shaped jewel, such as 4, arranged with its base outwardly, is that the ease and accuracy with which the jewel may be set is very much increased since, with a roller table 2 provided with a V-shaped seat and having a jewel of the proper triangular cross section and of the proper height from base to apex, when the jewel is inserted in the seat by the workman, he simply presses the jewel home, after warming the shellac, until the base coincides with the arcuate perimeter of the adjacent portion of the roller table 2, thus putting the escapement in original condition. In addition to the increase of facility and reater accuracy of adjustment of the jewel in its seat, a further advantage is obtained of sustaining and lat-- erally supporting the sides of the jewel, thus making it possible to use a jewel whose base or operative face is of minimum thickness, thus most nearly approaching perfection in escapement construction.

During its excursions, the roller table 52 carries the jewel into operative engagement with a pallet lever 7 having prongs 8, The jewel a engages the inner opposite faces 9 of the prongs 8, and in Fig. 1 these surfaces or faces 5) are shown as arcuate in outline. There is a rolling contact during operation between the operative corners of the jewel 4 when it is in engagement with one or the other surfaces 9 of the pallet lever 7.

An important feature of the present invention is the relation existing between the jewel 4E and the contact surfaces 9 of the lever 7, and this distinction is to be observed. hen the lever 7 is thrown against one or the other of banks 10, where it is held locked by the locking faces of the pallet stones, the jewel a when swinging will strike the extremity of the dovetailed, notched lever 9; the point of contact being preferably at the very tip. Thus the application of the force of the swinging roller table 2 is applied at the point most distant from the center of oscillation of the lever 7 or about its staff 7 and is maintained on the point of the lever until unlock is completed.

The initial movement of the lever T away from the adjacent bank, when moved under the impulse or blow from the jewel l, operates to unlock the pallet lever 7 from the scape-wheel 11. It will be observed that the force of theroller table acting through the jewel is acting upon the lever 7 with maximum efficiency because the point of contact between the jewel i and the lever contact surface 9 is most remote on the lever from the lever staff 7 and also closest the center of the balance staff, thus making a short lever unlocking a long lever. The consequence is that due to the long leverage the lever 7 is unlocked with the least resistance on the jewel 4t as it runs down incline of jewel with a disengaging action.

I have found that the space between the outer corners of the opposing dovetailed Contact surfaces 9 may be made very closely approximate, or may even be slightly less than the actual width of the base of the jewel 4, this clearing itself when entering the notch, and since the jewel 4 strikes the facing corner of a contact surface 9 of the lever at the extremity of the notch, then during the immediate co-action following, which results in the unlocking of the lever 7, the jewel rolls on the tip of the surface 9 after it has entered the space formed between the opposing contact surfaces 9. lVhen the lever is entirely unlocked from the scape-wheel 11, the lever will be oscillated by an impulse derived from the scapewheel and the impulsed lever will then quickly swing about its staff 7', so that what has been the following contact surface 9 will swing and drive the adjacent corner of the jewel 4. During the subsequent coaction of the driving contact surface 9 upon the jewel 4-, these engaged members will roll relatively upon each other, and just prior to the dis engagement of the jewel from the prong of the lever, the former will be subjected to a final impulse from the extreme corner of the pallet lever 7, at which moment the driving point of the contact surface 9 will have rolled from a point on the base or outer corner of the jewel to a point nearer the apex of the jewel and, therefore, nearer the balance center, so that the force of the pallet lever is expended with maximum efficiency at a point as far remote from the center of oscillation of the lever as is possible. The angular notch in the fork is slightly more acute than the angle of the jewel.

A guard or dart 1% swings into a passing hollow 13, freely, as the members cooperate, and after the members separate so that the roller table may continue its excursion, the lever 7 is prevented from overbanking by a peripheral stopping surface or safety roller 15 attached to or forming a part of the roller table 2.

For-the purpose of preventing the overbanking of the lever at the moment that the jewel swings past the ends of the prongs 8 of the lever 7 and after the safety roller 15 leaves the guard 11- in case of accidental tripping or unlocking, I form upon the transverse ends of the prongs S slight concaved surfaces 16 which will swing against the passing base of the jewel at; tiese surfaces interlocking with the jewel until such time as the latter has entered the space between the impulse faces 9 and the guard moves into the passing hollow 13. By making the safety roller somewhatlarger and the passing hollow somewhat smaller, I am enabled to avoid the horns ordinarily provided on the escape lover.

The ideal escapement is one which retards the oscillation of the balance the least, and my escapement provides for the reduction of retardation, since the unlock is accomplished nearer the balance center of a given impulse radius and with an oblique disengaging action. The impulse starts at the maximum distance from the center of the balance and well back in the fork, operating for most of its are on the jewel corner, advancing toward the center of the balance and finishing at the end of the fork, which is most desirable, giving an equal pressure on the jewel though the balance has been accelerated. The unlocking action is equal to taking place near the line of centers as the tip of the prong runs down the incline of the jewel, which is the ideal point for unlocking the escapement.

By my construction a very light lever, practically without horns, may be utilized which is a great advantage when timing in position. The impulse action of the fork facing on the impulse jewel almost identical with the action of the scape-wheel tooth of a chronometer on the impulse face of the jewel. The impulse is an oblique disengaging action, and the fork and dart being so light and requiring so little play in the notch, after the unlock is completed the lever overtakes the jewel very quickly which gives an exceptionally long impulse are, showing that this form of fork and roller action is particularly adapted to a very low angled and highly detached escapement, which is the goal. all watchmakers strive to attain.

In a 10 escapement with a 2 of lock and run, the impulse starts within 21F of the bank and is maintained through 54 of pallet arc, and even though the balance is moving with greater velocity, the final part of impulse is stronger than the start as point of contact changes from back in fork to point of fork, and from base of jewel to point near apex. The first part of the impulse is a disengaging action as the corner of the jewel runs down incline in the notch, which action is similar to starting impulse at the line of centers which is the ideal point to deliver the impulse. The jewel receives a blow when unlocked and the impulse takes place between two points of support, and when the balance has made a complete turn or rebanks outside of the prongs, these will strike still fart-her in on the jewel toward the center of the table, the short horns permitting a. greater free are.

From unlock to impulse there is less play of the jewel in the notch than in any other part of the action as the jewel lies obliquely between the points of contact and practically fills the space between them. The impulse jewel has two distinct arcs of action, one for unlocking and one for impulse. In fine watches this shape of jewel can very easily be made of a diamond which it is practically impossible to make with cylindrical or spherical form.

In Figss6 and 7 the dart 14 is shown as formed of wire having its ends secured in the lever; the dart point having curved sides which may be varied in degree to increase or decrease the effective length of the dart.

In Fig. 1 the table is shown as mounted on the stafl bottom-side up and the dart is mounted on the top side of the fork so that the entire safety action and also the fork and roller action are visible to the workman from the upper side of the watch.

In Fig. 3 in the single roller form the outside of the tip ends of the fork act as a guard against the perimeter of the table, and in case of accidental unlocking at the moment one of the tips is entering the passing hollow, the other tip engages the outer face or base of the jewel until the latter has safely entered the notch, thus preventing overbanking. The jewel is set in the passing hollow. One side of the table extends near the base of the jewel. If preferred, the notch in the fork may be made rectangular in form.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. In an escapement for time pieces, a pallet lever having a forked impulse end, an impulse roller, and a triangular jewel set in the roller, said jewel having its inner angle in a radial line bisecting the jewel, and its outer angles adapted to engage the inner surfaces of the fork with varying leverages.

2. In a time piece escapement, an impulse roller having a triangular jewel set in its periphery with its interior angles equi-distant from the radius of the roller passing through the interior angle of the jewel, and a pallet lever having a fork, angles at the opening of the fork, said fork having convexly arcuate inner sides which diverge away from the forked opening, said sides being adapted to alternately engage the ex terior angles of the jewel while driving, and said fork angles being adapted to be engaged by the sides of the jewel while being driven.

3. In a time piece escapement, a forked pallet lever and a roller table having an impulse jewel with sides diverging outwardly from a point in a radius of the roller table to form exterior angles, said sides adapted to engage the exterior outer angle of the fork at unlock, and said exterior angles adapted to be engaged by the interior of the fork sides at impulse.

4. In a time piece escapement, an impulse roller table having a wedge-shaped jewel fixed thereon with its acute base angles exposed outwardly, and a pallet lever having its contiguous end forked, the sides of said fork having sides diverging inwardly with convex curvature and adapted to co-act with the roller jewel with variable leverages.

5. In a time piece escapement mechanism, a roller table having a jewel, said jewel having a face, and sides intersecting said face to form the fork operating corners of the jewel, said sides converging toward a common point in the perpendicular which bisects the face of the jewel and coincides with a radius of the impulse roller, said point being located in the perpendicular at a distance from the base greater than the length of the base.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

EDWARD A. OOOHRAN.

WVitnesses G. H. STRONG, F. E. MAYNARD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Iatents,

Washington, D. 0. 

